ObjectUtils.java Source code

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/*
 * Copyright 2002-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

//package net.gqu.utils;

import java.lang.reflect.Array;
import java.util.Arrays;

/**
 * Miscellaneous object utility methods. Mainly for internal use within the
 * framework; consider Jakarta's Commons Lang for a more comprehensive suite
 * of object utilities.
 *
 * @author Juergen Hoeller
 * @author Keith Donald
 * @author Rod Johnson
 * @author Rob Harrop
 * @author Alex Ruiz
 * @since 19.03.2004
 * @see org.apache.commons.lang.ObjectUtils
 */
public abstract class ObjectUtils {

    private static final int INITIAL_HASH = 7;
    private static final int MULTIPLIER = 31;

    /**
     * Determine if the given objects are equal, returning <code>true</code>
     * if both are <code>null</code> or <code>false</code> if only one is
     * <code>null</code>.
     * <p>Compares arrays with <code>Arrays.equals</code>, performing an equality
     * check based on the array elements rather than the array reference.
     * @param o1 first Object to compare
     * @param o2 second Object to compare
     * @return whether the given objects are equal
     * @see java.util.Arrays#equals
     */
    public static boolean nullSafeEquals(Object o1, Object o2) {
        if (o1 == o2) {
            return true;
        }
        if (o1 == null || o2 == null) {
            return false;
        }
        if (o1.equals(o2)) {
            return true;
        }
        if (o1 instanceof Object[] && o2 instanceof Object[]) {
            return Arrays.equals((Object[]) o1, (Object[]) o2);
        }
        if (o1 instanceof boolean[] && o2 instanceof boolean[]) {
            return Arrays.equals((boolean[]) o1, (boolean[]) o2);
        }
        if (o1 instanceof byte[] && o2 instanceof byte[]) {
            return Arrays.equals((byte[]) o1, (byte[]) o2);
        }
        if (o1 instanceof char[] && o2 instanceof char[]) {
            return Arrays.equals((char[]) o1, (char[]) o2);
        }
        if (o1 instanceof double[] && o2 instanceof double[]) {
            return Arrays.equals((double[]) o1, (double[]) o2);
        }
        if (o1 instanceof float[] && o2 instanceof float[]) {
            return Arrays.equals((float[]) o1, (float[]) o2);
        }
        if (o1 instanceof int[] && o2 instanceof int[]) {
            return Arrays.equals((int[]) o1, (int[]) o2);
        }
        if (o1 instanceof long[] && o2 instanceof long[]) {
            return Arrays.equals((long[]) o1, (long[]) o2);
        }
        if (o1 instanceof short[] && o2 instanceof short[]) {
            return Arrays.equals((short[]) o1, (short[]) o2);
        }
        return false;
    }

    /**
     * Return as hash code for the given object; typically the value of
     * <code>{@link Object#hashCode()}</code>. If the object is an array,
     * this method will delegate to any of the <code>nullSafeHashCode</code>
     * methods for arrays in this class. If the object is <code>null</code>,
     * this method returns 0.
     * @see #nullSafeHashCode(Object[])
     * @see #nullSafeHashCode(boolean[])
     * @see #nullSafeHashCode(byte[])
     * @see #nullSafeHashCode(char[])
     * @see #nullSafeHashCode(double[])
     * @see #nullSafeHashCode(float[])
     * @see #nullSafeHashCode(int[])
     * @see #nullSafeHashCode(long[])
     * @see #nullSafeHashCode(short[])
     */
    public static int nullSafeHashCode(Object obj) {
        if (obj == null) {
            return 0;
        }
        if (obj instanceof Object[]) {
            return nullSafeHashCode((Object[]) obj);
        }
        if (obj instanceof boolean[]) {
            return nullSafeHashCode((boolean[]) obj);
        }
        if (obj instanceof byte[]) {
            return nullSafeHashCode((byte[]) obj);
        }
        if (obj instanceof char[]) {
            return nullSafeHashCode((char[]) obj);
        }
        if (obj instanceof double[]) {
            return nullSafeHashCode((double[]) obj);
        }
        if (obj instanceof float[]) {
            return nullSafeHashCode((float[]) obj);
        }
        if (obj instanceof int[]) {
            return nullSafeHashCode((int[]) obj);
        }
        if (obj instanceof long[]) {
            return nullSafeHashCode((long[]) obj);
        }
        if (obj instanceof short[]) {
            return nullSafeHashCode((short[]) obj);
        }
        return obj.hashCode();
    }

    /**
     * Return a hash code based on the contents of the specified array.
     * If <code>array</code> is <code>null</code>, this method returns 0.
     */
    public static int nullSafeHashCode(Object[] array) {
        if (array == null) {
            return 0;
        }
        int hash = INITIAL_HASH;
        int arraySize = array.length;
        for (int i = 0; i < arraySize; i++) {
            hash = MULTIPLIER * hash + nullSafeHashCode(array[i]);
        }
        return hash;
    }

    /**
     * Return a hash code based on the contents of the specified array.
     * If <code>array</code> is <code>null</code>, this method returns 0.
     */
    public static int nullSafeHashCode(boolean[] array) {
        if (array == null) {
            return 0;
        }
        int hash = INITIAL_HASH;
        int arraySize = array.length;
        for (int i = 0; i < arraySize; i++) {
            hash = MULTIPLIER * hash + hashCode(array[i]);
        }
        return hash;
    }

    /**
     * Return a hash code based on the contents of the specified array.
     * If <code>array</code> is <code>null</code>, this method returns 0.
     */
    public static int nullSafeHashCode(byte[] array) {
        if (array == null) {
            return 0;
        }
        int hash = INITIAL_HASH;
        int arraySize = array.length;
        for (int i = 0; i < arraySize; i++) {
            hash = MULTIPLIER * hash + array[i];
        }
        return hash;
    }

    /**
     * Return a hash code based on the contents of the specified array.
     * If <code>array</code> is <code>null</code>, this method returns 0.
     */
    public static int nullSafeHashCode(char[] array) {
        if (array == null) {
            return 0;
        }
        int hash = INITIAL_HASH;
        int arraySize = array.length;
        for (int i = 0; i < arraySize; i++) {
            hash = MULTIPLIER * hash + array[i];
        }
        return hash;
    }

    /**
     * Return a hash code based on the contents of the specified array.
     * If <code>array</code> is <code>null</code>, this method returns 0.
     */
    public static int nullSafeHashCode(double[] array) {
        if (array == null) {
            return 0;
        }
        int hash = INITIAL_HASH;
        int arraySize = array.length;
        for (int i = 0; i < arraySize; i++) {
            hash = MULTIPLIER * hash + hashCode(array[i]);
        }
        return hash;
    }

    /**
     * Return a hash code based on the contents of the specified array.
     * If <code>array</code> is <code>null</code>, this method returns 0.
     */
    public static int nullSafeHashCode(float[] array) {
        if (array == null) {
            return 0;
        }
        int hash = INITIAL_HASH;
        int arraySize = array.length;
        for (int i = 0; i < arraySize; i++) {
            hash = MULTIPLIER * hash + hashCode(array[i]);
        }
        return hash;
    }

    /**
     * Return a hash code based on the contents of the specified array.
     * If <code>array</code> is <code>null</code>, this method returns 0.
     */
    public static int nullSafeHashCode(int[] array) {
        if (array == null) {
            return 0;
        }
        int hash = INITIAL_HASH;
        int arraySize = array.length;
        for (int i = 0; i < arraySize; i++) {
            hash = MULTIPLIER * hash + array[i];
        }
        return hash;
    }

    /**
     * Return a hash code based on the contents of the specified array.
     * If <code>array</code> is <code>null</code>, this method returns 0.
     */
    public static int nullSafeHashCode(long[] array) {
        if (array == null) {
            return 0;
        }
        int hash = INITIAL_HASH;
        int arraySize = array.length;
        for (int i = 0; i < arraySize; i++) {
            hash = MULTIPLIER * hash + hashCode(array[i]);
        }
        return hash;
    }

    /**
     * Return a hash code based on the contents of the specified array.
     * If <code>array</code> is <code>null</code>, this method returns 0.
     */
    public static int nullSafeHashCode(short[] array) {
        if (array == null) {
            return 0;
        }
        int hash = INITIAL_HASH;
        int arraySize = array.length;
        for (int i = 0; i < arraySize; i++) {
            hash = MULTIPLIER * hash + array[i];
        }
        return hash;
    }

    /**
     * Return the same value as <code>{@link Boolean#hashCode()}</code>.
     * @see Boolean#hashCode()
     */
    public static int hashCode(boolean bool) {
        return bool ? 1231 : 1237;
    }

    /**
     * Return the same value as <code>{@link Double#hashCode()}</code>.
     * @see Double#hashCode()
     */
    public static int hashCode(double dbl) {
        long bits = Double.doubleToLongBits(dbl);
        return hashCode(bits);
    }

    /**
     * Return the same value as <code>{@link Float#hashCode()}</code>.
     * @see Float#hashCode()
     */
    public static int hashCode(float flt) {
        return Float.floatToIntBits(flt);
    }

    /**
     * Return the same value as <code>{@link Long#hashCode()}</code>.
     * @see Long#hashCode()
     */
    public static int hashCode(long lng) {
        return (int) (lng ^ (lng >>> 32));
    }
}